Podbel’skogo, St. Petersburg, 196608 Russia, e-mail vladchebotar@rambler.ru Acknowledgements: Supported by Russian Science Foundation (project No. 14-16-00146) A b s t r a c t Endophytic called bacteria are those colonizing the internal tissues of plants without causing disease and not rendering negative influence on its development. <...> There are great prospects for search, selection and study of new species of endophytic bacteria, improving the development of plants, with the aim of creating new microbial preparations for adaptive crop production. <...> Since bacterial endophytes colonize the same ecological niches in the plant as phytopathogenic microorganisms, they are a promising agent for biocontrol of phytopathogens. <...> Classical studies of biodiversity of endophytic bacteria based on a characterization of isolates obtained from internal plant tissues after surface sterilization. <...> It is shown that endophytic bacteria are capable of producing vitamins, have a number of additional properties necessary for the improvement of plant development, such as: regulation of osmotic pressure, regulation of stomata, modification of root development of plants, regulation of nitrogen nutrition of plants. <...> Endophytic bacteria are able to reduce or prevent the negative effects of pathogenic microorganisms on plants. <...> Inoculation of plants by endophytic bacteria is able to significantly reduce the harm caused to plants by pathogenic fungi, bacteria, viruses, insects and nematodes. <...> Unique strains of endophytic bacteria can be used directly for inoculation of seeds or seedlings, reducing, thus, the influence of biotic and abiotic factors on the plant, due to the active colonization of internal tissues of plants and subsequent positive biochemical and physiological effect on the plant. <...> While in endosphere, endophytes have a significant advantage over organisms that live in the rhizosphere and phyllosphere due to the stable pH, humidity, flow of nutrients and lack of competition from a large number of microorganisms. <...> For the inoculation of plants with endophytic bacteria do not require large amounts of inoculum, taking into account high specificity of such plant-microbe symbiosis and competitiveness of endophytic bacteria. <...> This technique can be very attractive for biotechnological productions, seeking the replacement of traditional chemical pesticides. <...> Keywords: endophytic bacteria, biodiversity, plant-microbial interaction, plant growth promotion biocontrol, secondary metabolites, the genome of bacteria, microbial preparations. <...> Associations of plants with beneficial <...>